350 at take off bogs,gurgles, won't plane.

dipthenet

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Jul 4, 2009
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My 350 at take off is bogging down. I can slowly get on plane by easing into it, then it will open up around 3k and take off. Cannot bury the throttle at all. Once on plane the boat runs great. Anyone have any ideas. I am not sure if its not getting enough fuel or too much. I checked the filter at the carb today, it was fine. also checked the main fuel filter that I replaced a few weeks ago and it looked fine. Thanks a lot
 

Fun Times

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Re: 350 at take off bogs,gurgles, won't plane.

My 350 at take off is bogging down. I can slowly get on plane by easing into it, then it will open up around 3k and take off. Cannot bury the throttle at all. Once on plane the boat runs great. Anyone have any ideas. I am not sure if its not getting enough fuel or too much. I checked the filter at the carb today, it was fine. also checked the main fuel filter that I replaced a few weeks ago and it looked fine. Thanks a lot
It kind of sounds like the accelerator pump inside the carb is not working right, They do brake some times inside the carb, And if that is it, That would mean less fuel.
 

cr2k

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Re: 350 at take off bogs,gurgles, won't plane.

Pull your flame arrester and have someone pump the throttle (boat does not have to be running to do this). Look in the carb throat you should see 2 streams of gas squirting in to the venturis. If not your accelerator pump is either worn out or plugged up, or the check ball is sticking open.

In either case if no fuel squirt, time for a rebuild.
 

BLDFW

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Re: 350 at take off bogs,gurgles, won't plane.

It kind of sounds like the accelerator pump inside the carb is not working right, They do brake some times inside the carb, And if that is it, That would mean less fuel.

I agree. Accelerator pump isn't working right. It could be the rubber has worn and it's not providing a full charge of gas down the carb. Not unusual for them to wear out. It might seem pretty daunting but it's a pretty easy fix. You can try replacing just the pump plunger alone or take the opportunity to rebuild the carb.
 

dipthenet

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Re: 350 at take off bogs,gurgles, won't plane.

Well,

I tested the pump like you all mentioned, and believe it or not it works. I guess thats a good thing but now I am wondering again on what it could be. I ended up running the boat for a bit today. With the same results as the last few days. One thing I forgot to mention was the fact that I ran old gas through the engine. Could that have gummed everything up in the carb? If so, should I try and runs some gumout through it? Thanks for the first suggestions anyway.
 

Bondo

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Re: 350 at take off bogs,gurgles, won't plane.

One thing I forgot to mention

Ayuh,.... How about What carb,..??
 

Showtime22

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Re: 350 at take off bogs,gurgles, won't plane.

When running look down the carb with out the flame cover and have a friend rev the motor in neutral. Do the lower butterfly on the carb open? They could be sticking. My motor 350 has had this issue. I needed to lube the lower intake butterfly.
 

cr2k

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Re: 350 at take off bogs,gurgles, won't plane.

If it's a Quadrajunk it probably needs rebuilding anyway. They don't like bad gas.
 

jtybt

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Re: 350 at take off bogs,gurgles, won't plane.

Pull the carb and turn it over (drain gas). There are a couple soldered up tubes on the bottom that leak. Dab some JB weld on em and let it set up. Makes it run too rich at low to intermediate throttle.
 

dipthenet

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Re: 350 at take off bogs,gurgles, won't plane.

Thanks to all.

New problem or same problem. No compression in #4 and #6. Oh boy, the fun of owning toys.
 

dipthenet

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Re: 350 at take off bogs,gurgles, won't plane.

Ok. So heres the latest.

Bad Starboard head. two valves are tuliped? The others need to be replaced as well. Need new water pump. Not sure on the port side head.Hundreds in with the marine mechanic. To repair and reassemble I am looking at around $2000. Now one side of the motor is somewhat rebuilt. No guarantee on the work. Boat was in the salt and shows for more potential problems. What would you do? Option 1, buy a new motor? Option 2, pay the $2000 to have it put back together and hope for the best? :confused:
 

jtybt

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Re: 350 at take off bogs,gurgles, won't plane.

You can buy a set of new vortec heads for under $1000.

One of the problems with the Q-jet is the secondary upper 'trap-door' spring set too loose allowing the doors to open too soon or too much. This causes a lean condition which raises the combustion temps and cause the sucked valves
 

Showtime22

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Re: 350 at take off bogs,gurgles, won't plane.

I would not want to pay 2ooo for the fix. I just spun a bearing on my crank and decided to replace my 350 rather than rebuild it myself. Craigslist had a lot of rebuilt 350's for under a grand. I got one that had 10,000 miles on it from a car for 500 bucks. I rented a cherry picker and bought a 50 dollar engine stand. Swapped over accessories and had it back together in 6 days. 350's are the best. I have a much newer motor in it now for around 600.

Goodluck.
 

Bondo

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Re: 350 at take off bogs,gurgles, won't plane.

Bad Starboard head. two valves are tuliped?

Ayuh,... She was runnin' Lean because of that Rottenchester,....
Detonation Melted the motor....
Whatever motor you decide on,... Replace that Carb too...
 

dipthenet

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Re: 350 at take off bogs,gurgles, won't plane.

Thanks Everyone.

That's what I was thinking.

Can you recommend a good replacement carb?

What are the differences between a marine and automotive 350?

I have the fresh water closed cooling system also. Can I just switch or does something else need to be replaced. Not sure i want to chance the current system knowing it was in the salt also. Should that be a concern? Thanks again. Never thought I would be doing all this in the first two months of boat ownership. Live and learn thats for sure.
 
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